A semiconductor used in electronic equipment or the like generates heat during operation, and the performance of electronic components may be reduced by the heat. Therefore, a metallic heat dissipating member is generally attached to a heat generating electronic component via a heat conductive sheet in the form of gel or soft rubber. In recent years, however, another method has been proposed in which a heat storage material sheet is attached to a heat generating electronic component so that heat is stored in the heat storage material sheet, and thus a heat transfer rate is reduced.
Patent Documents 1 to 2 propose heat storage rubber that incorporates microcapsules containing a heat storage material. Patent Document 3 proposes a member for countermeasures against heat. The member is obtained by coating the entire surface of a silicone elastomer with a coating material. The silicon elastomer includes a paraffin wax polymer and a heat conductive filler. Patent Document 4 proposes, e.g., a vanadium oxide containing trace metal such as tungsten as a heat storage material.